Make hg-fast-export (actually) work on Windows

Because on Windows sys.stdout is initially in text mode, any LF
characters written to it will be transformed to CRLF, which causes git
to blow up.  This change uses Windows platform-specific code to change
sys.stdout to binary mode.

hg-fast-export.py

@@ -11,6 +11,14 @@ import re
 import sys
 import os
 
+if sys.platform == "win32":
+  # On Windows, sys.stdout is initially opened in text mode, which means that
+  # when a LF (\n) character is written to sys.stdout, it will be converted
+  # into CRLF (\r\n).  That makes git blow up, so use this platform-specific
+  # code to change the mode of sys.stdout to binary.
+  import msvcrt
+  msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
+
 # silly regex to catch Signed-off-by lines in log message
 sob_re=re.compile('^Signed-[Oo]ff-[Bb]y: (.+)$')
 # insert 'checkpoint' command after this many commits or none at all if 0